I am having persistent issues with X in Fedora 10. Occasionally, when scrolling in Firefox or another application -- the window contents will stick (not scroll) and leave only a portion of the scrollable area scrolling (this area will be the only visibly updating area) and also sometimes regions of the screen (usually GTK areas such as everything but the scrolling region in Firefox) will vanish to solid grey rectangles. These issues occur in more than Firefox (although I have used it as my example.)
I'm guessing the culprit is the video driver (mine is from xorg-x11-drv-i810-2.5.0-4.fc10.i386)
Any help would be appreciated! Thanks!